Histiocytic sarcoma with central nervous system involvement in 6 cats

Area of Science:

• Veterinary Pathology
• Comparative Oncology
• Neuro-oncology

Background:

• Histiocytic sarcoma is an uncommon malignancy of myeloid origin.
• Central nervous system (CNS) involvement is rare in feline histiocytic sarcoma.

Observation:

• Six feline cases of CNS histiocytic sarcoma were characterized (4 post-mortem, 2 biopsies).
• Clinical signs were chronic and progressive, with tumors affecting the brain and/or spinal cord.
• Gross findings included neuroparenchymal swelling and distinct masses, with histological examination revealing pleomorphic neoplastic cells.

Findings:

• All cases showed positive immunolabeling for Iba1, confirming histiocytic origin.
• Multinucleate neoplastic cells were a consistent feature across all cases.
• Immunohistochemistry ruled out lymphoid and epithelial origins.

Implications:

• This study provides a detailed characterization of feline CNS histiocytic sarcoma, aiding in diagnosis and understanding of this rare condition.
• Further research is needed to understand the prognosis and treatment options for feline CNS histiocytic sarcoma.
• The findings contribute to the comparative oncology of histiocytic sarcomas in the CNS across species.